This invention relates to a pick-up type assembly for attaching an implement to a vehicle, such as a tractor.
Pick-up type hitch assemblies are known wherein the drawbar or the draft links are pivotal in a vertical plane about a fixed, transversely extending pivot. Such assemblies are described in U.S. Pat. No. 2,926,931; U.S. Pat. No. 2,983,523 and in U.S. Pat. No. 2,968,494. The problem with such assemblies is that the hook on the rear end of the drawbar or draft links moves downward and forward and thus, pivots out of the view of the operator. One solution to this visibility problem is the pick-up type drawbar assembly described in U.S. Pat. No. 3,863,955 wherein the hook end moves downward and to the rear and remains visible in its lowered position. However, the assembly described in U.S. Pat. No. 3,863,955 requires the use of a hydraulic cylinder with a stroke length nearly as long as the distance travelled by the hook end of the drawbar. Another drawback to this system is that the mechanical advantage of the system decreases as the drawbar is raised. This requires the use of two hydraulic cylinders, thus increasing the cost of the system, while wasting cylinder capacity when the mechanical advantage is greatest when the drawbar is lowered. Accordingly, it would be desirable to provide a pick-up type drawbar assembly which requires only a single hydraulic cylinder with a relatively short stroke length.